minix/lib/libsys/env_get_prm.c

   1 #include "sysutil.h"
   2 #include <string.h>
   3
   4 int env_argc = 0;
   5 char **env_argv = NULL;
   6
   7 static const char *find_key(const char *params, const char *key);
   8
   9 /*===========================================================================*
  10  *                              env_setargs                                  *
  11  *===========================================================================*/
  12 void env_setargs(int arg_c, char *arg_v[])
  13 {
  14         env_argc= arg_c;
  15         env_argv= arg_v;
  16 }
  17
  18 /*===========================================================================*
  19  *                              env_get_param                                *
  20  *===========================================================================*/
  21 int env_get_param(const char *key, char *value, int max_len)
  22 {
  23   message m;
  24   static char mon_params[MULTIBOOT_PARAM_BUF_SIZE]; /* copy parameters here */
  25   const char *key_value;
  26   int i, s;
  27   size_t keylen;
  28
  29   if (key == NULL)
  30         return EINVAL;
  31
  32   keylen= strlen(key);
  33   for (i= 1; i<env_argc; i++)
  34   {
  35         if (strncmp(env_argv[i], key, keylen) != 0)
  36                 continue;
  37         if (strlen(env_argv[i]) <= keylen)
  38                 continue;
  39         if (env_argv[i][keylen] != '=')
  40                 continue;
  41         key_value= env_argv[i]+keylen+1;
  42         if (strlen(key_value)+1 > (size_t) max_len)
  43               return(E2BIG);
  44         strcpy(value, key_value);
  45         return OK;
  46   }
  47
  48   /* Get copy of boot monitor parameters. */
  49   m.m_type = SYS_GETINFO;
  50   m.m_lsys_krn_sys_getinfo.request = GET_MONPARAMS;
  51   m.m_lsys_krn_sys_getinfo.endpt = SELF;
  52   m.m_lsys_krn_sys_getinfo.val_len = sizeof(mon_params);
  53   m.m_lsys_krn_sys_getinfo.val_ptr = (vir_bytes)mon_params;
  54   if ((s=_kernel_call(SYS_GETINFO, &m)) != OK) {
  55         printf("SYS_GETINFO: %d (size %zu)\n", s, sizeof(mon_params));
  56         return(s);
  57   }
  58
  59   /* We got a copy, now search requested key. */
  60   if ((key_value = find_key(mon_params, key)) == NULL)
  61         return(ESRCH);
  62
  63   /* Value found, see if it fits in the client's buffer. Callers assume that
  64    * their buffer is unchanged on error, so don't make a partial copy.
  65    */
  66   if ((strlen(key_value)+1) > (size_t) max_len) return(E2BIG);
  67
  68   /* Make the actual copy. */
  69   strcpy(value, key_value);
  70
  71   return(OK);
  72 }
  73
  74
  75 /*==========================================================================*
  76  *                              find_key                                    *
  77  *==========================================================================*/
  78 static const char *find_key(const char *params, const char *name)
  79 {
  80   const char *namep, *envp;
  81
  82   for (envp = params; *envp != 0;) {
  83         for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
  84                 ;
  85         if (*namep == '\0' && *envp == '=')
  86                 return(envp + 1);
  87         while (*envp++ != 0)
  88                 ;
  89   }
  90   return(NULL);
  91 }
  92